The study is a cooperative, randomized trial to determine the efficacy of Vi polysaccharide in preventing typhoid fever in Nepal. The Biometry & Mathematical Statistics Branch's involvement in this study was to design the data collection forms, and assist in the data management and the analysis with the study investigators from NICHD and Nepal. In March 1986, 6,908 volunteers from five villages in Nepal were randomly vaccinated with either the Vi polysaccharide or pneumonococcal vaccine. These volunteers were visited every three days for the next two years to verify their health status and to detect any typhoid cases prior to treatment. Blood cultures were done on anyone with a fever of three days duration. Randomization scheme was broken in August, 1988 and cross-immunization of the volunteers took place in September and October, 1988. The data is now being analyzed and a manuscript will be submitted for publication.